I had a 2012 Lariat 4x4 Ecoboost with 18" tires. I just traded it in on a 2014 Platinum, 4x4 Ecoboost with 20" tires as a retirement gift to myself. The old truck was getting great fuel mileage, 18-21 on interstate. This new truck, 2800 miles on it right now, does good to hit 16 mpg and that is taking it easy. They both have the 3.55 rear end. My routes and driving habits are the same also.

Should a two inch tire size difference have such a drastic difference in fuel economy?

 

Your rims are 2" bigger, but are you tires really 2" taller?

 

My 11 ECO averaged 18.4 over 72000 miles. My 13 with 12300 miles 15.7 average driving same roads. FORD did something to the programming as my 13 doesn't have the power the 11 had either.
ITS not your tires

 

No......... What he means is his rims are 20". Old ones were 18". Tire height same...approx. 32"

 

My 13 has plenty of power and my MPG is probably in the 19-20 mpg range on the highway, whereas around town it SUCKS, and I put 34's on mine.


Weird about MPG, some get good, some not with the same engine/options. I know driving habits have a lot to do with it. But the same person driving 2 trucks with same options/engine should get similar mpg's. Or you would think so?????

 

Your comparing a broken in truck to a non broken in truck.

Wait until you get some miles on it and then re compare...

 

How heavy are ur 18" tires and wheels and compare that to how heavy ur 20" wheels and tires are that will make a big difference. Are they the same exact configuration. Like the other post said you need to give it time to break in

 

is the truck heavier with options? seems like a new platinum with bigger/heavier rims and options would probably not get as good of mileage, extra weight kills that MPG

 

broken in or not your not gonna gain 5 mpg when is is so called "broken in"

 

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